If you make the manifold yourself (its not that hard) the floats need to run horizontally and you'll need to incline the carbs by 25 degrees.

You should be ok loosing the vacuum as the lumenition dizzies used on pintos etc dont run them, you just block the pipe up. It is only really used when the choke is on creating more suction to the vacuum diaphragm creating more advance on warm up for better running.